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D01-27

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Math Expert
Joined: 02 Sep 2009
Posts: 49303

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16 Sep 2014, 00:12
00:00

Difficulty:

5% (low)

Question Stats:

91% (00:58) correct 9% (01:39) wrong based on 128 sessions

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It takes computer A 6 hours and 40 minutes to finish a job. If computer B can process the same job in 10 hours, how long will it take, for both computers working together, to finish the job?

A. 6 hours and 20 minutes
B. 5 hours and 10 minutes
C. 4 hours and 40 minutes
D. 4 hours
E. 3 hours and 20 minutes

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Math Expert
Joined: 02 Sep 2009
Posts: 49303

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16 Sep 2014, 00:12
1
Official Solution:

It takes computer A 6 hours and 40 minutes to finish a job. If computer B can process the same job in 10 hours, how long will it take, for both computers working together, to finish the job?

A. 6 hours and 20 minutes
B. 5 hours and 10 minutes
C. 4 hours and 40 minutes
D. 4 hours
E. 3 hours and 20 minutes

After rewriting the time needed to finish the job in minutes, we construct an equation:
$$\frac{1}{400}+\frac{1}{600} = \frac{3+2}{1200} = \frac{5}{1200} = \frac{1}{240}$$

240 minutes equals 4 hours.

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Intern
Joined: 14 Jun 2018
Posts: 36
Location: India

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03 Sep 2018, 18:32
The Solution is helpful. btw which level questions are these?
Math Expert
Joined: 02 Sep 2009
Posts: 49303

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03 Sep 2018, 23:49
Shridhyey wrote:
The Solution is helpful. btw which level questions are these?

According to the stats this particular question is 700-level. You can check the difficulty level of a question and additional stats on it in the first post.
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Re: D01-27 &nbs [#permalink] 03 Sep 2018, 23:49
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D01-27

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